Hummingbird Bioscience to Collaborate with Merck on Clinical Trial of Anti-VISTA Antibody HMBD-002 in Combination with KEYTRUDA® (Pembrolizumab) for Treatment of Cancer

HOUSTON and SINGAPORE,Oct. 25,2021 --Hummingbird Bioscience,an innovative clinical-stage biotech company focused on developing precision therapies against hard-to-drug targets to improve treatment outcomes,today announcedit has entered into a clinical trial collaboration agreement with Merck.

Under this collaboration,Hummingbird will evaluate the safety,tolerability,and anti-tumor activity of its novel anti-VISTA antibody,HMBD-002,in combination with KEYTRUDA® (pembrolizumab),Merck's anti-PD-1 therapy,in patients with triple negative breast cancer (TNBC),non-small cell lung cancer (NSCLC) and other cancers with high VISTA expression. HMBD-002 is anticipated to enter a Phase 1 clinical trial in 2021.

VISTA is a co-inhibitory immune checkpoint receptor that is involved in suppressing an anti-tumor immune response. Overexpression of VISTA in the immune cells in tumors has also been associated with acquired resistance to other checkpoint therapies,such as anti-PD1 therapies. TNBC and NSCLC were identified as priority indications for clinical investigation based on the unmet need for new treatment options and widespread expression of VISTA in these tumor types. HMBD-002 is the only IgG4 isotype anti-VISTA antibody currently in development. It is precisely engineered to bind to VISTA at a specific site that is predicted to be essential for ligand-binding and function,and thereby inhibits VISTA by neutralizing its immunosuppressive activity without depleting other VISTA expressing cells that play many important roles in the immune system. Preclinical studies have demonstrated potent anti-tumor activity both as single agent and in combination with PD-1 therapy.

"Our preclinical studies have shown that VISTA in combination with PD-1 therapy can enhance anti-tumor activity. We look forward to initiating clinical trials for HMBD-002 as we aim to develop new treatment options for patients who do not respond to existing therapies," said Piers Ingram,Chief Executive Officer and co-founder of Hummingbird.

About HMBD-002

HMBD-002 represents a unique first-in-class anti-VISTA neutralizing antibody,and the only IgG4 isotype anti-VISTA antibody currently in development. It was engineered to bind to VISTA at a specific site that was predicted to be essential for ligand-binding and function,thus inhibiting VISTA and neutralizing its immunosuppressive activity without depleting VISTA expressing cells that play many important roles in the immune system. Preclinical models have shown that HMBD-002 as a monotherapy inhibits tumor growth and significantly prolongs progression-free survival,with no observed toxicity. HMBD-002 has also shown enhanced anti-tumor activity when used in combination with anti-PD-1 therapy. HMBD-002 is being developed for multiple cancers that have strong evidence of VISTA mediated suppression both as a monotherapy and in combination with PD-1 inhibitor. The Cancer Prevention and Research Institute of Texas (CPRIT) has awarded Hummingbird a US$13.1 million product development grant to advance HMBD-002 into clinical trials.

About Hummingbird Bioscience

Hummingbird Bioscience is an innovative clinical-stage biotech company focused on developing precision therapies against hard-to-drug targets to improve treatment outcomes. We harness the latest advances in systems biology and data science to better understand and solve the underlying causes of disease and guide development of our therapeutics.

Enabled by our proprietaryRational Antibody Discovery platform,we discover and engineer precision therapies against optimal yet elusive epitopes that have not been successfully drugged,unlocking novel mechanisms of action. We are advancing a rich pipeline of first- and best-in-class precision therapies in oncology and autoimmunity,in collaboration with global partners in academia and industry.

Our highly experienced,multidisciplinary teams in Houston,Texas and Singapore,span antibody discovery,pharmacology,production,data science and clinical development. Together we aim to accelerate the journey of new drugs from concept to clinical care.

For more information,please visitwww.hummingbirdbioscience.com,and follow Hummingbird on LinkedIn and Twitter (@hummingbirdbio).